Rebased: Prune linked requirements when others are fixed

1 files changed, 48 insertions, 0 deletions

diff --git a/ir/be/becopyheur4.c b/ir/be/becopyheur4.c
index 96ba3ec..a76b41f 100644
--- a/ir/be/becopyheur4.c
+++ b/ir/be/becopyheur4.c
@@ -137,6 +137,8 @@ typedef struct co_mst_irn_t {
 
 	/** The number of uses of this node that have a register restriction to be compressed. */
 	int                comp_use_count;
+
+	bool               uncompressable : 1; /**< Mark this node as not compressible (for debug purposes). */
 } co_mst_irn_t;
 
 static double scaled_edge_weight(const aff_edge_t * edge)
@@ -158,6 +160,7 @@ static int compressable_uses_count(co_mst_env_t *env, const ir_node *irn)
 {
 	// To do this, we use the nodes' out edges, so verify they are correct
 	// Note: This is only required once, not for every node, but keep it here for now
+	// Todo Move this to initialization as the irg structure is not changed here
 	assure_irg_properties(irn->irg, IR_GRAPH_PROPERTY_CONSISTENT_OUT_EDGES);
 
 	int comp_uses_count = 0;
@@ -1232,6 +1235,9 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c)
 	for (unsigned i = 0, n = env->n_regs; i < n; ++i) {
 		/* skip ignore colors */
 		unsigned col = order[i].col;
+
+		bool col_compressible = env->get_compression_reqs && bitset_is_set(env->compressible_regs, i);
+
 		if (!bitset_is_set(env->allocatable_regs, col))
 			continue;
 
@@ -1242,6 +1248,7 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c)
 		for (size_t idx = 0, len = ARR_LEN(c->n); idx < len; ++idx) {
 			const ir_node   *irn  = c->n[idx];
 			co_mst_irn_t    *node = get_co_mst_irn(env, irn);
+			affinity_node_t *aff_node = get_affinity_info(env->co, irn);
 
 			assert(!node->fixed && "Node must not have a fixed color.");
 			DB((dbg, LEVEL_4, "\t\tBringing %+F from color %d to color %d ...\n", irn, node->col, col));
@@ -1256,6 +1263,37 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c)
 			if (good) {
 				materialize_coloring(&changed);
 				node->fixed = 1;
+
+				// Prune compression requirements if applicable
+				if (env->get_compression_reqs) {
+					compression_req_t req = env->get_compression_reqs(node->irn);
+
+					// We are handling compression requirements
+					// Todo Can this be factored such that we do not need to check this explicitly?
+
+					// Remove restrictions for compressible registers
+					if (!col_compressible
+							&& (req == comp_req_register_subset || req == comp_req_2addr_register_subset)
+							&& !node->uncompressable) {
+
+						node->uncompressable = true;
+
+						c->comp_reg_use_count -= node->comp_use_count;
+						c->comp_reg_restr_count -= node->comp_reg_restricted;
+					}
+
+					// Disable 2-address requirement edge if the register requirement cannot
+					// be fulfilled anymore; this is only applicable if the current color is not from the
+					// compressible color subset
+					if (!col_compressible
+							&& req == comp_req_2addr_register_subset) {
+						co_gs_foreach_neighb(aff_node, neighb) {
+							if (neighb->aff_type == aff_edge_compression) {
+								neighb->pruned = true;
+							}
+						}
+					}
+				}
 			} else {
 				reject_coloring(&changed);
 			}
@@ -1268,6 +1306,16 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c)
 		for (size_t idx = 0, len = ARR_LEN(c->n); idx < len; ++idx) {
 			co_mst_irn_t *node = get_co_mst_irn(env, c->n[idx]);
 			node->fixed = 0;
+
+			// Replace pruned requirements
+			if (env->get_compression_reqs) {
+				if (node->uncompressable) {
+					node->uncompressable = false;
+
+					c->comp_reg_use_count += node->comp_use_count;
+					c->comp_reg_restr_count += node->comp_reg_restricted;
+				}
+			}
 		}
 
 		/* try next color when failed */